For two hours, President Bush listened to contrasting visions of the U.S. future in Iraq. Gen. David H. Petraeus dominated the conversation by video link from Baghdad, making the case to keep as many troops as long as possible to cement any security progress. Adm. William J. Fallon, his superior, argued instead for accepting more risks in Iraq, officials said, in order to have enough forces available to confront other potential threats in the region.

The polite discussion in the White House Situation Room a week ago masked a sharper clash over the U.S. venture in Iraq, one that has been building since Fallon, chief of the U.S. Central Command, which oversees Middle East operations, sent a rear admiral to Baghdad this summer to gather information. Soon afterward, officials said, Fallon began developing plans to redefine the U.S. mission and radically draw down troops.

One of those plans, according to a Centcom officer, involved slashing U.S. combat forces in Iraq by three-quarters by 2010. In an interview, Fallon disputed that description but declined to offer details. Nonetheless, his efforts offended Petraeus's team, which saw them as unwelcome intrusion on their own long-term planning. The profoundly different views of the U.S. role in Iraq only exacerbated the schism between the two men.

"Bad relations?" said a senior civilian official with a laugh. "That's the understatement of the century. . . . If you think Armageddon was a riot, that's one way of looking at it."

For Bush, the eight months since announcing his "new way forward" in Iraq have been about not just organizing a major force deployment but also managing a remarkable conflict within his administration, mounting a rear-guard action against Congress and navigating a dysfunctional relationship with an Iraqi leadership that has proved incapable of delivering what he needs.

Although the administration has presented a united front, senior officials remain split over whether Bush's strategy will work in the long term. Bush gambled that a "surge" of 30,000 troops in the streets of Baghdad and the western province of Anbar would establish enough security to give "breathing space" to Iraq's sectarian leaders to find common ground.

But as Petraeus and Ambassador Ryan C. Crocker deliver progress reports to Congress tomorrow, the questions they are likely to face are the same ones asked internally: How long should the troop buildup last? When should U.S. forces start to come home? Should the United States stand by Iraqi Prime Minister Nouri al-Maliki or seek another leader? What are the hidden risks of the emerging alliance with Sunni tribal leaders? What is the best outcome Washington can hope for at this point?

Amid the uncertainty, the overriding imperative for Bush these past eight months has been to buy time -- time for the surge to work, time for the Iraqis to get their act together, time to produce progress. In Washington's efforts to come to grips with the war it unleashed, the story of these months is one of trying to control the uncontrollable. And now as a result of a casual idea by Petraeus that hardened into an unwelcome deadline, the administration finds itself at a pivotal moment.

"All the outreach and consultations did not reset as much time on the Washington clock as we had hoped," said Peter D. Feaver, who was a National Security Council strategic adviser until July. "Rather than buying us more time, the D.C. clock seemed to accelerate after the president's speech."

A Strategy With Few Supporters

The president was somber as he took his place behind the lectern in the White House library the night of Jan. 10. It was an awkward address. He stood alone in the corner talking into a camera. His subdued tone, appropriate for ordering thousands more men and women into battle, worried some aides who feared it was not persuasive.

It did not take long to figure out just how unpersuasive it was. As Bush said good night and headed upstairs to bed, the reviews came in heavily negative, even among Republicans. The notion that the president was sending even more troops to Iraq after an antiwar public turned control of Congress over to the Democrats exasperated many in the capital. The visceral reaction induced near-panic among some in the White House.

"The concern of some people -- me -- was the floor was going to break politically," said Peter H. Wehner, then White House director of strategic initiatives. "We put all our eggs in the surge-Petraeus basket. The speech just didn't seem to move anything, and, if anything, it seemed to deepen the problem."